To the Editor: We would like the opportunity to comment on the recent communication by Maniker et al. regarding hydroxyapatite cement (HAC)-BoneSource (Howmedica Leibinger, Inc., Dallas, TX) (6). Having been involved with basic and applied research that validated and introduced this technology to clinical craniofacial surgery (2,3,5), we were dismayed by several statements that appear to be inaccurate, misinformed, and as a consequence, misleading. Maniker et al. report a single case in which a frontal-cranial reconstruction, described in detail, resulted in an implant removal and failure to reconstruct the frontal bone defect. It seems to us that the authors could have prevented the reported outcome with a better understanding of this new technology, including following the information contained in the package insert. In addition, there are now more than 70 published reports and technical papers on the technology, and numerous workshops and presentations have been available. A large and growing group of surgeons have insight and experience with this material. Although Maniker et al. claim "meticulous attention to the manufacturer's instructions," the implant package insert, provided at the time of this case, clearly recommends use of a closed suction drain in defects 4 cm2 or larger to prevent wound fluid accumulation. This is also intuitively appropriate after elevating large scalp flaps in craniofacial surgery. Secondly, they chose not to employ an underlying support of mesh, such as used in traditional acrylic reconstructions. The authors state that, "The failure of this material to set in the face of exposure to fluid during the first 4 hours after application and migration of the paste has been documented." What they fail to recognize is that the material documented in their Reference 4 is not even HAC-BoneSource, but a completely different material. HAC-BoneSource does set in the presence of cerebrospinal fluid (CSF), such as a small dural tear or a low-pressure flow in pituitary surgery. HAC-BoneSource should not be used in areas of large dural defects, which would lead to high-flow volume CSF accumulation. As clearly stated in these studies, a surgically dry operative field is a requirement for success. Excessive wound fluid would preclude the "in-situ set and reaction," which is the fundamental biophysical reaction. As alluded to by Maniker et al., the use of sodium phosphate in place of water as a diluent (which has now been used clinically in the United States for the last 6 months) will dramatically speed up the setting time and allow some leniency in a less than dry field. With regard to the authors' and the associated responders' comments on cost, they seem to be out of context and lacking a relevant critical assessment. A certain surgical procedure or technique is rarely the only way of accomplishing a therapeutic goal. Alford and Netscher (submitted for publication), and the Altro Group (1), a consultant qualified in the field, have performed relevant cost identification analyses and found that the cost of using HAC-BoneSource compares favorably with the costs associated with autologous bone grafts. Surgeons performing cranial reconstructions should review these pertinent, although not perfect, studies. The clearance to market this product in the United States was approved by way of a 2-year multicenter clinical investigational device exemption study that demonstrated a 97% implant survival rate (7). Certainly, further careful long-term clinical outcome studies need to be performed to evaluate this new technology. Yet, if patient selection criteria require a biomaterial alloplast with long-term success and true "tissue integration," then HAC-BoneSource is the first and only current readily available implant that is validated for cranial defect repair. The casual observer would question the editorial imperative to publish a single case report of a negative outcome that seems to be attributable to technical error. Such reports only serve to obscure appropriate and relevant information from being heard and understood. Hopefully, this is not an indication of the "big crunch" as described by Goodstein (4). We sincerely urge all readers and clinicians to carefully evaluate and understand this new technology, which we think can be used with great success and long-term positive outcomes in the appropriately selected surgical patient. Craig D. Friedman Facial Plastic Surgeon; Philadelphia, Pennsylvania Peter D. Costantino Otolaryngologist; New York, New York ACKNOWLEDGMENTS Dr. Craig Friedman and Dr. Peter Costantino are founders of Osteogenics, Inc. They currently serve as paid consultants to Howmedica-Leibinger; however they receive no royalties on sales of BoneSource hydroxyapatite cement, or any other Howmedica-Leibinger product.